The present invention relates to a vacuum release valve for positioning on a line between a pool suction inlet and a pump for pumping pool liquid from the inlet and along the line, and also relates to a vacuum release method. When the terminology xe2x80x9cpoolxe2x80x9d is used in the present specification it includes swimming pools, spas, ponds, lakes etc., especially when the aforementioned have recreational applications. When the terminology xe2x80x9cinletxe2x80x9d is used throughout the specification it can include one or more inlets of various types.
Pools of various types are known to have one or more suction inlets where pool water is sucked along a line via a pump to filtration, aeration, chemical treatment and other type of equipment, prior to being returned to the pool via one or more return outlets.
In more recent pool designs, some of the suction inlets are positioned at a bottom or lower region of the pool. Very recently developed pool cleaning systems, known as in-floor cleaning systems, have one or more suction inlets which suck pool water therethrough and any debris and pollutants entrained therein are cleaned from the water by being pumped to a filtration and/or treatment station.
Some of these inlets have relatively small opening areas and, when large volumes of water are being pumped therethrough, very high suction forces at the inlet can be induced. These forces can be so extreme that if a pool user contacts the inlet by any part of their body, they can be held thereagainst, unable to be dislodged even by excessive force. Where the suction inlet is located at or adjacent to a bottom of the pool, the user can thus be submerged with the risk of drowning, grievous bodily harm etc.
U.S. Pat. No. 5,991,939 discloses a pool safety valve which is designed to bleed air into the suction line of a pool when the suction pressure exceeds a predetermined value. The arrangement disclosed is, however, somewhat complex in that a pair of opposing valve slide plates, which are normally biased apart by a spring arrangement, must be urged away from opposing sealing end plates by the suction force in the pool suction line. The valve of U.S. Pat. No. 5,991,939, because of its relative complexity, is somewhat complex to manufacture and operate and would therefore be relatively expensive.
U.S. Pat. No. 6,098,654 also discloses a flow blockage suction interrupt valve to instantaneously introduce atmosphere into a suction piping system of a pool when a dangerous vacuum condition is detected. The valve of this patent is even more complex in construction and operation than that of U.S. Pat. No. 5,991,939. In the valve of U.S. Pat. No. 6,098,654, vacuum is applied to a spring loaded trigger pin, which draws that trigger pin down in the valve, and this in turn releases a locking mechanism between a main valve piston and the remainder of the valve. Once this locking mechanism is released, a spring forces the main valve piston downwardly, and this allows ambient air to flow through the valve, past the piston and into the swimming pool circulation system. Because of its complexity and the close tolerances required, this valve would be quite costly to manufacture and is complex in operation.
Increased complexity often means that a valve is more likely to seize or fail in use.
In a first aspect the present invention provides a vacuum release valve for positioning on a line between a pool suction inlet and a pump for pumping pool liquid from the inlet and along the line, the valve including a valve member that is urged by the pump into a sealing position during normal pumping of pool liquid from the inlet to the pump and such that the pool liquid does not flow across the valve;
wherein, when a predetermined level of vacuum is induced in the line, the valve member is moved out of the sealing position by the vacuum so that a fluid is allowed to flow through the valve to release the vacuum.
In the valve of the present invention, the valve member is urged by the pump into a sealing position during normal pumping of pool liquid from the inlet to the pump. This means that a very simple valve and valve member configuration can be adopted and the complexities of prior art configurations avoided. For example, a simple valve ball and valve seat arrangement can be employed (as described below).
In one preferred application of the invention in a swimming pool, when or if a user blocks the suction inlet by a part of their body (or if other debris blocks the inlet) whilst the pump is operating, the pump continues to pump the liquid in the line thus inducing a vacuum (typically a partial vacuum) in the line. The level of vacuum induced then typically rapidly reaches the predetermined level. The valve of the present invention can release that vacuum by allowing a fluid (eg. a gas) to flow back into the line, thereby breaking the vacuum and releasing the user (or debris). In effect, the flow of fluid can either cause the pump to lose prime and hence suction force (eg. when the fluid is a gas) or can reduce the pressure in the line to a level where the user (or debris) can be freed from the inlet (eg. when the fluid is a liquid).
The terminology xe2x80x9cpredetermined levelxe2x80x9d does not equate as such with any specific relative or even an absolute level of vacuum, but is typically a level of vacuum reached when there is a blockage at the inlet. However, in other applications partial blockage may cause the predetermined level of vacuum to be reached. Thus the terminology should be interpreted broadly.
It should be appreciated that the invention has application with suction lines in a wide variety of pools including natural and artificial ponds (eg. to prevent fish and other marine life from being harmed), in spas, and even in commercial applications. Thus, when xe2x80x9cpool liquidxe2x80x9d is referred to, it is not necessarily limited to water, and could be bodies of organic fluids etc.
Typically the valve allows a flow of fluid in the form of air or other ambient gas thereacross to release the vacuum, although in some embodiments the flow of fluid may also be a flow of liquid (eg a restorative side water flow from a separate source). However, for ease and cost of operation it is most preferred that the flow of fluid is a flow of air (typically atmospheric, ambient air, being readily available).
Preferably the valve is a one way valve, more typically a one way ball valve, with the valve member being a ball. Thus, in a normal pool liquid pumping operation, the ball seals fluid flow thereacross by sitting against a valve seat, and is only moved away from the seat when the predetermined level of vacuum is induced in the line, thereby enabling the fluid flow.
In one preferred variation the valve houses a plurality of valve members, typically a plurality of ball valve members. This enables the valve to provide for multiple re-uses, prior to the valve having to be dismantled for servicing. In this regard, each ball valve member can be separated from an adjacent ball valve member by a separator pin.
Typically the plurality of ball valve members are aligned one above the other, linearly above the valve seat. Preferably, when the predetermined level of vacuum is reached, the ball sitting at the valve seat is drawn past the seat and preferably into a ball capturing chamber. In accordance with the present invention, rather than having to discard the valve or dismantle the valve to reset the ball at the seat, a user can remove the lowermost separator pin, the next uppermost ball can then drop into place at the seat (eg. under the influence of gravity) and the valve is therefore ready for use again.
Preferably, when the predetermined level of vacuum is reached, the ball sitting at the valve seat is drawn past the seat and into a ball capturing chamber, and wherein an upper part of the valve can be rotated relative to a lower fixed part of the valve and, at a given rotational position, the upper part can then be moved downwardly relative to the lower part such that the valve seat passes over the ball in the ball capturing chamber to once again position the ball at the seat, and the upper part can then be moved upwardly relative to the lower part so that the valve is again ready for use.
Preferably the upper part is urged downwardly against a spring positioned between the upper and lower parts, which spring tends to urge the upper part away from the lower part and move it up once the ball has again been positioned at the seat.
Preferably the valve is located in an auxiliary line located laterally to the line extending between the inlet and pump. As such, when pool liquid is pumped past the auxiliary line a partial vacuum is also induced in the auxiliary line. Typically the valve seat is positioned such that this partial vacuum has the effect of drawing the ball against the seat, enhancing sealing thereat.
Preferably the valve is also oriented such that when the fluid is caused by the vacuum to flow across the valve the ball is forced past the seat. In this regard, the ball is, in effect, sucked out of its sealing position at the seat by the suction force induced in the line, and is moved to a position which then enables fluid to be drawn across the valve to the pump, thus releasing the vacuum.
Preferably the seat is adapted to only allow the ball to move therepast once the predetermined level of vacuum has been induced in the line. Preferably the seat is formed from a resilient but deformable material, which deforms as the ball passes and restores to its former shape once the ball has passed.
Preferably the seat is in the form of an annular inwardly protruding shoulder or sealing ring in the valve, which preferably engages an underside of the ball such that the ball can only move therepast when the predetermined level of vacuum is reached. Thus, preferably the retention shoulder is oriented such that, for normal pump operation, the ball is not moved out of sealing engagement with the seat.
As an alternative to the retention shoulder arrangement, the ball can be spring loaded, or another retention system such as plurality of leaf springs etc. can be employed, but in any case a sealing arrangement is still employed.
In a second aspect the present invention provides a method of using a valve to release a vacuum induced in a line between a pool suction inlet and a pump for pumping pool liquid from the inlet and along the line, the valve having a valve member that is held in a valve closed position by the pumping of pool liquid in the line, the member being movable from the closed position to an open position, the method including the step of facilitating valve member movement to the open position, to thereby allow a flow of fluid into the line, when a predetermined level of vacuum is induced in the line, to in turn release the vacuum.
Preferably the flow of fluid is a flow of air or other gas, and preferably the method is facilitated by a vacuum release valve according to the first aspect of the invention (and its various preferred forms).